* Started on task_preview widget
* Finish task_preview widget
Finalized the code for the task_preview widget. Options and theme
variables should be allowed now.
* Changes according to review
* Improved opts
* Fixed vars to be backwards compat
* Update docs
* Old playerctl cli backend added as option
* Move files into directory and only require playerctl lib on enable
* Added wrapper functions to select backend based on args
* Switched 'player_stopped' signal to 'no_players' in CLI backend
* Added support for setting interval directly in enable() for CLI backend
* Update docs for both backends